I have a bunch of single dose tubes with valves which I love. I am using them to store beans after I open a new bag (roughly 4-7 days after roast date).

What happens the valves fail?
Is air able to get in?
Are the valves even necessary for beans 5+ days old?

If the valve fails oxygen will get inside. But first you might want to ask whether the valves keep oxygen out to begin with. They might not.

Is letting oxygen in a problem with some valves?

It's only a problem if the oxygen that gets in is undesirable.

Materials have varying degrees of oxygen permeability. Sometimes the seals are imperfect as well. A classic example is the beer bottle crown cap, especially the twist-off variety. You crack open a beer and hear the pop-fizz of escaping CO2. Surely the pressurized bottle keeps oxygen out, right? Nope. It gets in.

So how well constructed are the lids on your tubes? What material is the valve made out of? Silicone rubber, a common choice, has a relatively high permeability to oxygen. How are you getting the oxygen out of your tubes in the first place?

Unfortunately it's a difficult thing to test. But for sure if the valve fails completely oxygen will get inside.

This is neither here nor there, but when I read this thread's title I thought this valve had something to do with the French painter.

jbrady3324 wrote:Are the valves even necessary for beans 5+ days old?

Chances are that if you're storing fleshly roasted beans that you're single dosing you're likely storing them for less than a week.
Go by taste, I wouldn't worry too much.